Compressor regulator



Aug. 29, 1939. c. s. BAKER COMPRESSOR REGULATOR Filed Aug. 25, 1957 2 Sheets-Sheet l www mm. mm

INVENToR haz'lescez'. En-4% H 5 ATI-OR N EY.

www @A @www www Alg 29, 1939. c. s. BAKER 2,171,285

COMPRESSOR REGULATOR Filed Aug. 25, 1937 2 Sheets-Sheet 2 H IS ATTORNEY.

Patented Aug. 29,

courussoa naomron charles s. Baker. comm, N. Y., mmm u rngersoIl-Band Company, Jersey City, N. J., a oorporatlon of New Jersey prima Aunt ss. mi. serai N. mina -sz (ci. zat- 4) This invention relates to regulators for motor driven fluid compressors, and more particularly to regulator for varying the speed o! the motor to. conform generally to the required output of the fluid compressor.

A portable compressor unit usually consists of a fluid compressor and an internal combustion engine adapted to drive the compressor. 'Ihe compressor delivers fluid under pressure to a receiver tank which forms a part of the unit, until a predetermined high iluid pressure is built up in the receiver tank. When this pressure is reached a device provided on the compressor stops the discharge of fluid from the compressor to the receiver tank (commonly termed unloading) and will unload and reload at frequent intervals, and

each time the compressor begins to reload, the engine accelerates to its maximum speed. The

result is that the engine continually swings back jana forth between its idling speed and its max- "imm rated speed making the operation unit unsteady and uneconomical.

of the It is an object of the present invention to provide means whereby the compressor unit may reload when the load is light without immediately accelerating to the maximum engine speed.

Another object is to provide means whereby the compressor unit may accelerate to and run at any motor speed between minimum and maxlmum to maintain corresponding rates of discharge of air into the receiver.

e It is a further object to provide a means which will, under the ordinary loading, unloading and under a'heavy load.

Still another object is to provide a regulating mechanism which will regulatethe speed setting of thel governor in accordance with variations oi' the pressure in the receiver.

These and other objects will be readily apparent in the following specification of which the drawings form a part.

Similar reference numerals refer to similar parts in the drawings.

Figure 1 isa view partly in elevation and partly in section illustrating the present invention as applied to a portable compressor unit. The governor is increased in size in order to show the details more clearly.

Figure 2 is a view in section of the regulating device shown in Fig. 1 constructed in accordance with the principles of this invention, and

Figure 3 shows in longitudinal section the unloading `device shown in Fig. 1.

The portable compressor unit is shown in Figure 1 and consists of a fluid compressor i mounted on a frame l supported by wheels 5. An internal combustion engine 'l drives the compressor I. The inlet pipe il supplies the fluid to be compressed to the compressor Iv and the conduit i3 delivers the compressed iluid from the compressor to the receiver tank i5. An unloading and re- `loading device is interposed between the pipe ii and the compressor i. The details of this unloader are illustrated in Fig. 3 and will be explained hereinafter.

The speed of the internal combustion engine 1 is regulated by the governor, generally indicated at Il, and consists of a shaft 2i lwhich is directly connected to the cam shaft (not shown) of the engine and has an extension 23. A gear 25 is secured to a iiange 21 on the shaft 2l by the bolts 29. Weights 3i are fulcrumed at 3i5 on ears 33 which form a part of the gear 25. As the speed of the engine` increases the centrifugal force moves ,the weights to their outermost position. As the weights move to this position, the plate 35 having a recess 31 surrounding the shaft extension 23 moves out from the shaft extension 23. Since the rollers 36 mounted on the levers supporting the weights 3i move outwardly as the governor spring is compressed, motion of the plate 35 is transmitted through an antifriction bearing 352 to a plate 354 formed integrally with a pin 356 slidably `mounted in the shaft extension 23 and coaxial therewith. ,f

'Ihe plate 354 has a clevis 39 surrounding and pinned to a lever 4i which is fulcrumed on the base of the motor 'I at 43. At the opposite end of the lever 4i is a .tie-rod 45 controlling the butterfly projection 49 intermediate the fulcrum and tie rod end. y

As is customary in centrifugal governors the weights 3| are resiliently held in, their retracted position and to this end a spring 9i is provided. A casing 9| having a bore 93 extending therethrough and communicating at one end with a recess 99 is secured to the frame of the motor 1.

The plunger 91 extends through the bore 93 and v,

has a flange 99 within the recess99. Spring 9| rests on the shoulder 99 at one end and pushes a member 93 against the projection 49 on the lever 4|. Fulcrumed on the casing 9| at 91 is a lever 99 whichhas a hooked portion 99 bearing on the external end of the plunger 91;v The clvis'ed tierod `1| is pinned to the other end of the lever 99 and connects this lever with the regulator lever erally at 19 regulates the position of the regulator lever 13 which in turn regulates the tension on the spring 9| and thus the speed setting of the governor.

The details of the regulating mechanism are f best illustrated in Fig. 2. With reference thereto it will be noted that it consists of a casing 11 secured to the motor frame by the bolts19 and is provided with a bellows chamber 3| closed by a head 93. The interior of the bellows chamber 3| is connected directly to the receiver tank by a conduit 99 secured to an oriiiced bushing 91 which is in turn secured in the passage 99 leading directly into the bellows chamber. 'I'he bushing 9] is provided with an orice 99 to restrict the fluid coming from the receiver. n

Extending through a passage 9| in the head 93 into the bellows chamber is a plunger rod 93.

- A piston member 99 is secured to the end of the shaft within the bellows chamber. One end of a bellows 91 is secured to the piston 99 in airtight relationship, and the opposite end of the bellows is secured in airtight relationship between the casing 11 and the head 93, in order that no media in the bellows chamber 9| may pass into the bellows proper.

Near the head 93, in the casing 11, is a passage 99 communicating with a passage |9| in' the head 93. A bushing |93 is secured .by threads to the head 93 and has an orifice |94, which is larger in area than the orifice 99, for restricting the flow of fluid leaving the bellows chamber 93. On the external end of the plunger rod 93 is a clevis |99 which is rotatably fastened to the lever |91 by the pin |99. The pinv |99 also serves to connect the regulator lever 13, fulcrumed on an extension provided on the head 93 at to the plunger rod 93. With this pin connection it is, therefore, possible to have vrelative rotation between the levers 13 and |91 and the plunger rod 93. A guardi3 forms a part of the head 83 and extends around the connection between the levers 13 and |91 and the end of the plunger rod 93. In order to regulate the outward movement of the shaft a bolt |9 threadedly engages the The regulating mechanism indicated geny 2,171,995 valve 41 in the fuel intake of the engine. When guard ||3 and may be locked in pomtion by the lock nut ||1.

In the upper part of the casing 11 is a recess ||9 having an enlarged portion |2| .in which is secured a diaphragm |23 by a plate |29 attached tc the casing by any suitable means, suchas the bolts |21. A conduit |29 Joins the conduit 99 and is connected to the receiver tank I9 by a conduit |39, shown inlll'ig.- l. This conduit |29 is secured-'ln a passage |3| opening 'into the diaphragm chamber |33. It will thus be seen that the pressure existing in the receiver tank I9 will also be maintained in the diaphragm chamber |23. 'The casing 11 has a threaded bore |35, leading into the recess ||9 adapted to receive a guide bushing |31, for a plunger |39 which extends into the recess and has secured thereto a follower |9| bearing against the diaphragm |23.

Within the recess, the bushing |31 has a flange |43 onI which a spring |49 rests, the opposite end of the spring bearing against the follower |4 The bushing |31 is provided with a lock nut |41 in order to maintain it in a fixed position. The plunger |39 extending outside the bushing |31 has a portion |49 of reduced diameter, the outer end of which is threaded to receive a regulating' bushing |9| and a locking means such as the nut |93.` The lever |91 is provided with a passage |99 through which kthe reduced portion |49 of the shaft |39 passes, and a seat r|91 to receive a spring |99 bearing against the lever and the bushing 19|.

Resting on the shoulder formed on the plunger |39, where the reduced portion |49 begins, is a slidable abutment |9I freely movable on the shaft extension |49 and having a bored-out recess |93. The lever |91 is normally pushed against the abutment |9| by the spring |99. In order to permit free movement of the lever |01 about the pin |99, and a constant contact point between that lever and the abutment |9i, a recessed surface |99 is formed on the end of the lever |91 which prevents the tip end of the lever from touching the abutment. On the lever |91, intermediate the shaft |49 and the fulcrum |99, is a button valve |91 which is so placed with respect to the orifice |94 in the metering bushing |93 that under normal conditions the button obstructs the orifice and at least to some degree prevents escape of fluid from the bellows chamber.

In order to lock the apparatus in certain positions a locking cam and handle |99 is pivotally mounted on the head 93 and may be moved into position to lock lever 13 in position whereby maximum tension in the governor spring 9| is assured;

'I'he lever |91 is provided with projecting lugs |1| and |13 adapted to bear against the head 93 and to draw the button valve |91 entirely away from orifice |94, the purpose of -which will be apparent when the operation of the regulator is described.

Referring now more particularly to Fig. 3 the unloading and reloading device |1 at the inlet to the compressor consists of a casing |19 which connects at its upper end to the pipe (Fig. 1) and at its lower end leads directly to the compressor 1. A portion of the casing |19 extends within the outer walls thereof and `forms valve seats |11 and a guide for the cylindrical unloading valve |19. j

An opening |9| in the casing is closed by the plate |93 provided with a recess |99 in which the spring |31 rests. The other end of spring |91 bears against the valve |19 normally tending to maintain the valve in the open position shown in l'ig.3. Inthispositiontheiluidmsymter from thepipe Il andpassaroundtheribs Illintothe passage III leadingdirectlytothecompressor.

A pistonchamber Illissecuredtothecasing I1l and communicates with the opening Ill provided in the wall of the casing and forms a seat for the valve i12 when the valve is in its open position. In slidable engagement with the wall of the piston chamber is a piston Il1, adapted to transmit its motion to the valve i12 by the shaft Ill formed integrally with valve I1I.

An auxiliary valve body 2li closes the open end of the piston chamber III andhas a passage 2n leading into the piston chamber. The pipe 2li connects the interior of the auxiliary valve cham,- ber 2li with the receiver tank. The auxiliary valve 2I1 normally rests on the seat 2 provided in the valve chamber and prevents the entrance of fluid under pressure from the receiver tank to the piston chamber through the passage 222-.

Normally the valve 221 is maintainedon its seat f by the member 2i. which transmits the pressure of the spring 2i I compressed between the head 2i! on the shank of member 2 Il and the bushing 2li. The bushing 2I1 threadedly engages the auxiliary valve chamber.- 2li and provides anad- .lustable seat 2i! against which the valve 2I1 bears when the pressure In the receiver tank is suilicient to move the valve against the compression of the spring. The bushing 2Il. which threadedly engages the bushing 2I1ls provided with a passage 2li of larger diameter than the diameter of the member 2 Il so that any pressure existing in the valve chamber may be relieved to atmosphere.

Operation Iof the device will now be described. Generally speaking, the motor driven compressor resembles prior arrangements f or vregulating in that when the discharge pressure of the compressor I reaches a predetermined maximum, the unloading mechanism I1 operates to check the compressor intake,A and upon a `drop in pressure in the receiver I5 toa predetermined minimum, the unloading mechanism I1 operates to reopen the intake to permit the compressor I to resume pumping. l The manner in which this is effected ls as follows:

Pressureuid conveyed through the pipe 2|! from the tank vI5 exertsforce against the upper face of the valve i221 .at the seat 2li, which is suillcient to overcome slightly the force of the spring 2I I. The instant the valve 201 starts to move under the influence of this force. the entire diameter of the valve 201 is exposed to the full discharge pressure and the valve 221 is thereby caused to move quickly .to itslower seat 2l! in which position it is held until the pressure drops suillciently to be overcome by the compression of the spring'2I I. Upon assuming its position at the lower seat 2 I 9, pressure Huid is conducted through the port 203 to move the piston |91 and valve I1! against the tension of the spring |81 to the' closed position of valve i12. In `this position the valve |19 has completely checked the flow of air or other gas to the passage I9I and the compressor I is unloaded.

Upon release of the valve 221 to the position at which it rests on the seat 209, the motor fluid escapes through the passage 202 to atmosphere by way of the passage 2li in the bushing 2li about the member 2Il. The accompanying reduction in pressure permits the piston |91 to return to the position shown in `lfig. 3 and under 3 the influence of the spring |21, valve Ill retur'nstoitsopenpositionpermittingairos'gasv which causes the lever 4I to rotate about its pivot l andthroughthelinklltooperatethebutterny valve l1.

Since 'a spring II is provided to oppose the. outward throw of the weights II of the governor. `the speed of the engine 1 varies accordingly with the characteristics of the spring li.

It is the function of the regulating mechanism to change the characterstics of the governor spring 0I so as to produce a certain cycle of operation which, in this instance, is a function of the receiver pressure and the speed of the motor. Brieiiy stated, this cycle is as follows: Starting with a predetermined minimum pressure in the receiver Ii at which the mechanism I1 operates to load the compressor I in the manner above-dcribed, motor 1 is adapted to speed up from an idling speed to its maximum permissible speed, assuming that the pressure in the receiver Il does not increase. Upon an increase of pressure in thereceiver Il the engine 1 slows down progressively until -a predetermined maximum pressure is reached in the receiver Il, at which point the speed of the engine reaches its minimum lpermissible speed and the mechanism I1 operates to unload the compressor I. The regulating mechanism thereupon holds the engine 1 at its minimumlspeed, while the pressure drops to a value at which the valve 2li operates to reload the compressor by means of the loading and unloading valve I1 as above described.

It is most desirable that at this point in the cycle a delay should occur in the speed-up of the engine. In this instance the delay is a function of a further drop in the receiver pressure Ii. During this predetermined further drop in pressure the engine continues to maintain its minimum speed. Thereupon the engine is accelerated under the control of the regulating mechanism 1I. Its speed varies inversely as the pressure in the receiver I5; that isA to say, as the pressure in the tank II rises the speed of the engine drops. At 4the predetermined minimum pressure at which the compressor loads, the motor does not speed up unless the pressure actuall decreases. This is due to the holding device. The compressor will not unload unless the air demand is less than the compressor output at minimum speed and until the demand increases the loading and unloading cycle will be maintained at minimum speed. At such time as the air demand increases the pressure will begin to drop and/at a predetermined pressure the regulating mechanism will unlock and the motor will speed up and momentarily equal or approach maximum speed, but will immediately stabilize at a speed (and pressure) where the compressor output equals the air demand. In other words, the speeding up does not occur when the compressor loads up,

nor does the compressor unload when minimum speed is reached, but rather at a slightly higher pressure. It is possible for the pressure to build up to the locking point and if the air demand increases slightly the pressure will begin to fall and the motor stay at minimum speed until the speed uppressure is reached. Each time that the pressure in the tank I5 reaches its predeterminedmaximum, this-cycle will be repeated.

To produce this action the regulating mechanism 415 operates in the. following manner:

Diaphragm |23 is always exposed to the receiver pressure being connected to the receiver I5 by the pipes |29 and |30. The diaphragm is always balanced by thetension of the spring |45 which. of course, will vary with the pressure on the opposite side of the diaphragm. Accordingly, the plunger |39 moves into and out of the chamber |2| pulling with it the end |51 of the lever |01. Motion of the lever |01 brings thev button valve |91 closer to or farther from the escape orifice |04, restricting it more or less, depending upon a drop or rise respectively in the receiver pressure. There is constantly a small amount of air from the receiver I5 leaking into the chamber 9| through the orifice 09 and its escape from the chamber 9| depends upon the restriction at the oriiice |04 caused by the valve |51. Thus, if such restriction is relatively great a considerabley pressure can build up in the chamber 9|. In that case the flexible bellows 91 is compressed causing the rod 05 to move outwardly and to actuate the lever 13 and link 1| attached to the bell crank 59 to move the plunger 51 in a direction to compress the governor spring 5|. This changes the characteristics of the governor in that it has the eiiectof stiifening the spring 5| and tends to open the butteriiy valve 41 to increase the power of the engine and cause a corresponding speed-up.

Inasmuch as speeding up the engine 1 will increase the pumping capacity of its direct connected compressor there should be either an increase in pressure in the tank |5 or a slowing up in the dropping oi' pressure therein, depending upon the demand for air or'rate at which it is being used. Simultaneously, as the rod |05 moves outwardly, there is some slight tendency for the button valve |51 to uncover the orifice |04, which tends to reduce the pressure in the chamber 9| and prevents the bellows 91 from continuing to collapse indeilnitely or, at least. to the extent permitted by the stop screw I5.

From this it will be seen that the movement of the rod |05 at one end of the lever |01 and the plunger |39 at the other end of that lever, have a partially neutralizing effect which is resolved into a certain tension in the governor spring 5| to correspond to any given receiver pressure. This is as it should be, inasmuch as the receiver pressure is the measure of the demand for air and the speed, and within certain ranges the speed of the engine 1 controls the production of compressed air by the compressor ditions are accordingly entirely under the control of and automatically adjusted by the regulating mechanism 15.

Under certain conditions of very light load, it is impossible to lower the speed of the engine to correspond with the demand for air, inasmuch as it is impractical to reduce the speed of the engine beyond certain limits as is well known.

Accordingly, the tension of the governor spring 5| is adjusted so that its minimum tension (when the plunger 51 has retracted to its limit) slows These corn` the engine down to its idling speed or thereabout.

` Assuming that the demand for air is such that *the pressure still continues to rise to the-prede termined .maximum allowable pressure, thenit is thefunction of the unloading mechanism i1 with its associated valve v2|i| to shut of! the intake thereby preventing the compressor from continuing to compress air. I

As has been described above in connection with the cycle of operation, it is desirable to maintain the speed of the engine 1 at a minimum as the pressure in the'receiver tank .I5 drops to some value less than that at which the mechanism |1 acts to reload the compresser. For this purpose the regulator mechanism 15 is adapted to lock, as it were, the lever |01 temporarily so that the valve |61 no longer aiects the orifice |04 thereby maintaining substantially a constant p ressure within the chamber 9|. This has the effect of maintaining the plunger rod 93 inactive temporarily, so that the minimum pressure is maintained at the governor spring 6|. This locking effect is produced as follows:

When the aforesaid predetermined maximum pressure exists in the chamber |33, it pushes the plunger |39 outwardly to its most extreme position, at which point the abutment |5| pushes the lever |01 to open wide the orifice |04. Air is thus evacuated from the chamber 9| to a value which has substantially no effect upon the bellows 91. The governor spring 6| reacts upon the plunger 51, bell crank 69, link 6| and lever 13 to retract the plunger rod 93 and 'pull the end of lever |01 adjacent the pin |09 up against the face of the plate 83. The abutment |1| acts as a fulcrum to then pull the button valve |51 still farther away from the orifice |04 and simultaneously to compress the spring |59. This outward motion of the valve |61 is limited by the provision of lug |13, which also bears against the face of plate 93. In this position the regulator mechanism is entirely out of action and stays so because there is no further control of the oriiice |04. Such control can only be eiIected by such a reduction in pressure in the chamber |33, which will cause the spring |45 to pull the plunger |39 and the nut |5| against the end of the lever |01 with suflicient force to overcome the force of the governor spring against the pin |09 tending to hold the valve |01 away from the orice |04. The tension in the spring |45 controls this operation and it is regulated by the degree to which its guide bushing |33 is screwed into or out of the casing 11.

The minimum pressure at which the lever |01 will be pulled down to cause the valve 51 to again control the oriiice |04 is determined by the position of the nut |5| which is adapted to pull against the recessed end |59 of that lever. If it is desired to lower this minimum pressure, the nut |5| is unscrewed.

As has been indicated above, it is desirable that the pressure at which the valve |51 begins to control the orifice |04 so as to change the engine speed, should be some value less than that at which the mechanism |1 is set to reload the compressor I. This permits the compressor to start pumpingat a low engine speed which in many instances is sucient to carry existing load. One advantage of this delay is that the engine does not so frequently speed up to rebuild the receiver pressure to its predetermined maximum and a saving in fuel is effected thereby.

When starting the engine cold it is desirable to have some means to maintain some extra pressure in the governor spring ll and this is provided by the cam I", which when rotated forces the lever 'Il to a position in which the plunger i1 is pushed against the end oi the spring Il, allowing the engine to operate at a relatively ,high speed.

It is understood that the construction above described is a preferred embodiment oi' the invention and that many changes which do not de-l part irom the scopeand spirit of the invention will occur to those skilled in the art.

I claim: r

1. A regulator `for a motor driven iluid compressor having aspeed governor, a pressure responsive device vfor controlling and varying the speed setting ofthe governor in accordance with the-variations of the discharge pressure of the compressor while the compressor is loaded, means to unload the compressor at a predetermined .maximum discharge pressure and to reload the compressor at a predetermined low discharge pressure, and means to lock said pressure responsive device at a predetermined high discharge pressure of the compressor until a predetermined minimum discharge pressure is reached.

2. A regulator for a motor driven iluid compressor comprising a pressure responsive device for controlling and varying the speed setting oi' the governor in accordance with the variations of the discharge pressure of the compressor while the compressor is loaded, means to unload the compressor at a predetermined maximum disf charge pressure and to reload the compressor at a predetermined low discharge pressure, and means to lock said pressure responsive device inoperative With respect to the governor at a predetermined high discharge pressure of the compressor and until a predetermined low discharge pressure is reached below said reloading pressure.

3. A regulator for a motor driven iluid compressor having a governor. means responsive to variations in the discharge pressure of the compressor to control and vary the governor while thecompressor is loaded, means to unload the compressor at al predetermined maximum pressure and to reload the compressor at a predetermined the pressure responsive device inoperative at a predetermined high pressure and operative at a predetermined minimum pressure, and adjust-I able means to regulate the pressure range within which the last said means operates. K

5. vA regulator for a motor driven iluid compressor having a governor, a pressure responsive device for controlling and varying the speed setting of the governor in accordance with variations in the discharge pressure of the compressor while the compressor is loaded, means to unload the compressor at a predetermined maximum 'pressure and to reload the compressor at a predetermined low pressure, adjustable ymeans to predetermine the pressures at which the last said means operates, means to render the pressure responsive device inoperative at a predetermined pressure not exceeding the predetermined maximumpressure and until a predetermined minimum pressure is reached, and adjustable means to regulate the pressures at which last said means operates. v

6. A regulator ior4 a motor driven iluid com pressor having` a governor, a pressure responsive device vfor controlling and varying the speed setting oi' the governor in accordance with variations in the discharge pressure of the compressor while the compressor is loaded, means to unload the compressor at a predetermined maximum discharge pressure and to reload the compressor at a. predetermined low discharge pressure, adjustable meansto determine the pressure at which the last said means'operates, and means to render the pressure responsive device inoperative at a predetermined pressure not exceeding the predetermined maximum discharge pressure and'until a predetermined discharge pressure is reached.

7. A regulator for a motor driven fluid compressor having a governor, a pressure responsive device for controlling and varying'the speed setting of the governor in accordance with variations in the discharge pressure oi' the compressor while the compressor is loaded, means to unload the compressor at a predetermined maximum dis; charge pressure and to reload the compressor at` a predetermined low discharge pressure, and means to render the pressure responsive device inoperative.y

8. A regulator for a motor driven fluid compressor having a governor, pressure responsive means to control and vary the speed setting of the governor in accordance with variations of the discharge pressure of the compressor while the compressor is loaded, means to unload and reload the compressor within a predetermined range oi' compressor discharge pressures, and means to lock the first said means to render it inoperative within a different predetermined discharge pressure range. y

9. In a regulator forV a motor driven uid compressor having a governor, means responsive to variations of the discharge pressure of the com- .sure responsive means to control and vary the speed setting of the governor adapted to maintain the governor while the compressor is loaded at a minimum speed settingwithln a predetermined range of discharge pressures of the compressor to permit the compressor to reload at a minimum motor speed.

11. A regulator for a motor driven iluid compressor having a governor comprising a pressure responsive device for controlling and varying the speed of the governor in accordance with variations in the discharge pressure oi the compressor while the compressor is loaded, means to unload the compressor at a predetermined maximum pressure and to reload the compressor at a predetermined low pressure, means to lock the pressure responsive device to render it inoperative at a predetermined high pressure to permit the governor to maintain the motor speed at a minimum and unlock the pressure responsive means to permit the governor to accelerate the speed of the motor to a maximum when a predetermined minimum pressure is reached.

12. A regulator for a motor driven iluid compressor having a governor comprising a pressure responsive device having various controlling positions for controlling and varying the speed setting of the governor in accordance with variations in the discharge pressure of the compressor i0 while the compressor .is loaded, means to unload the compressor at a predetermined maximum pressure and to reload the compressor at a predetermined low pressure, means to maintain the pressure responsive device in one controlling position at certain predetermined discharge pressures, and means to control operation of the last said means.

13. In a governor speed setting regulator fo a motor driven compressor comprising casings having chambers therein, pressure responsive means in each chamber, separate means lto transmit movement of the pressure responsive means, means connecting the separate means, venting means for one chamber, means on the connecting means to render the venting means ineffective, and means to connect the connecting means to the governor.

14. In a governor speed regulator for a motor driven compressor comprising a casing having a0 chambers subjected to the discharge pressure of the compressor, pressure responsive means in each chamber, separate means to transmit movement of the pressure responsive means, means to relieve the pressure in a chamber, and means actuated by said separate means to render the pressure relieving means inoperative..

15. In a motor driven fluid compressor, a governor to control the speed of the motor, a pressure responsive device for controlling the characo teristics of the governor in accordance with variations in the discharge pressure of the compressor, means to vent said pressure responsive device, and means controlled by said pressure responsive device to render the venting means in- 45 effective.

- 16. In a regulator for a motor driven fluid compressor having a governor and means to unload and reload the compressor at predetermined discharge pressures and a pressure responsive device to control the speed setting of the governor in accordance with the variation of the discharge pressure of the compressor having chambers therein and including pressure responsive means in said chambers, inter-connected levers 'asso- 55 ciated with the pressure responsive means and movable thereby, venting means in one of said chambers, a valve to open and close said venting means controlled by one of said levers, and means to connect said inter-connected levers to the govw ernor.

1'7. In a regulator for a motor driven fluid compressor having a governor and means to unload and reload the compressor at predetermined discharge pressures, and a pressure responsive de- 55 vice to control the speed setting of the governor in accordance with the variation ofthe discharge pressure of the compressor having chambers therein, means to vent one of said chambers, and means to close said vent when the discharge pres- 70 sure oi' the compressor reaches'a predetermined minimum pressure.

18. In a regulator for a motor driven compressor having a governor, means to unload the compressor at a predetermined high discharge pressure of the compressor, a pressure responsive device to control the speed setting of the governor in accordance with variations of the discharge `pressure of the compressor having chambers and including means to vent a chamber, pressure responsive means in all said chambers, and means controlled by said pressure responsive means to prevent said means from venting said chamber when the discharge pressure of the compressor reaches a predetermined minimum pressure.

19. In a regulator for a motor driven iiuid compressor having a governor, means to unload the compressor at a predetermined maximum discharge pressure to reload the compressor at a predetermined low discharge pressure of the compressonand a device to control the speed setting of the governor in accordance with variations o! the discharge pressure of the compressor having chambers subject to the discharge pressure of the compressor and including venting means for a chamber, pressure responsive means in said chambers,A means associated with said pressure responsive means to prevent .venting by said venting means when the discharge pressure of the compressor reaches a predetermined minimum pressure and assure venting by said venting means when the discharge pressure of the compressor reaches a predetermined high pressure, adiustablemeans to regulate the pressures at which said last means operates, and means connected with said venting preventing means to directly control the governor speed setting.

20. In a regulator for a motor driven iluid compressor having a governor, means to unload the compressor at a predetermined maximum discharge pressure and to reload the compressor at a predetermined low discharge pressure of the compressor, and a device to control the speed setting of the governor in accordance with variations of the discharge pressure of the compressor having chambers subject to the discharge pressure of the compressor and including means to vent a chamber, pressure responsive means in each said chambers, means associated with said pressure responsive means to transmit movement 'thereof to the governor, and means controlled by the last said means to open and close said y venting 1 means.`

,Uimum discharge pressure and to reload the compressor at a predetermined low discharge pressure `oi' the't'compressor, means to predetermine the unloading and reloading discharge pressure, and a device to control thespeed setting of the governor having chambersfsubject to the discharge pressure of the compressor, pressure responsive means in said chambers, plungers controlled by said pressure responsive means, inter-connected levers connecting said plungers, means to transmit movement of said levers to the governor to vary the speed setting thereof, venting means for a chamber, means associated with' said levers to open and close said venting means in accordance with variations of the discharge pressure of the compressor in said chambers, and means to predetermine a minimum discharge pressure at which said last means will maintain said venting means closed.

22. -In a regulator for a motor driven fluid -compressor having a governor and a receiver to which the compressor discharges, a device in communication with the receiver to unload the compressor at a predetermined maximum pressure in the receiver and to reload the compressor at a predetermined low pressure in the receiver, means to adjust the predetermined unloading and reloading pressures, and a device to control the speed, setting of the governor having chambers in communication with the receiver, pressure responsive means in each chamber, plungers moved by said pressure responsive means, means associated with said plungers to predetermine the receiver pressure at which said pressure responsive means move said plungers, and meansto transmit movement of said plungers to the governor to vary the speed setting thereof.

23. In a regulator for a motor driven iiuid compressor having a governor and a receiver to which the compressor discharges, a device in cornmunication wi-th the receiver to unload the compressor at a predetermined maximum pressure in the receiver and to reload the compressor at a predetermined low pressure in the receiver, means to adjust the predetermined unloading and reloading pressures, and a device to control the speed setting of the governor having two chambers in communication with the receiver and including a diaphragm in one chamber, a bellows in the other chamber, a series of levers, a plunger in the diaphragm chamber movable by said diaphragm, a plunger rod in said bellows chamber movable by said bellows, a vent in said bellows chamber, a series of inter-connecting levers connecting said plungers, a valve on one of said levers to open and close said vent, means to connect one of said levers to the governor to vary the speed setting thereof in accordance with movements of the plunger and plunger rod, and means to adjust the pressure at which said plunger will move tothereby vary the pressure at which said vent is opened and closed.

24. In a regulator for a motor driven compressor having a governor and a receiver to which the compressor discharges iiuid under pressure, a device acting in response to variations of the pressure of the iiuid in the receiver to unload the compressor at a predetermined maximum pressure Vand to reload the compressor at a predetermined low pressure, means to predetermine the unloading maximum and the reloading low pressure, and a device to control the speed setting of the governor having two chambers in constant communication with the receiver and including a pressure responsive means in each chamber, movable means in each chamber controlled by the respective pressure responsive means, means connecting said movable means, venting means in one of said chambers, controlling means on said connecting means i'or said venting means, means associated with said connecting means to vary the speed setting of the governor in accordance with the relative movements of said movable means, and adjustable means on one of said movable means to regulate said controlling means. I

25. In a motor driven iluid compressor, a governor to control the speed of the motor, a governor spring, and a pressure responsive device for controlling the characteristics of the governor spring while the compressor is loaded comprising a member operable in response to changes in the discharge pressure of the compressor, pressure operated means for regulating the tension of said governor spring, and means jointly controlled by said member and said pressure operated means for controlling the pressure for operating said pressure controlled means.

26. In a motor driven iluidcompressor, a governor to control 7the speed of the motor, and a pressure responsive device for controlling the characteristics of the governor in accordance with variations in the discharge pressure of the compressor while the compressor is loaded.

- 27. In a governor speed setting regulator for a motor driven compressor comprising a casing having chambers therein, pressure responsive means in each chamber, separate means to transmit movement of the pressure responsive means, means to connect one oi the last said means to the governor, venting means for one of the chambers, and means associated with the separate means transmitting movement of the pressure responsive means in the other chamber to open and close the venting means.

28. Ina governor speed regulator for a motor driven compressor comprising a casing having chambers therein, pressure responsive means in each chamber, means to connect one ot said pressure responsive means to the governor, means to vent one of said chambers, and means controlled by the pressure responsive means in the other chamber to regulate opening and closing of the venting means.

29. In a governor speed regulator for a motor driven compressor comprising a casing having chambers therein, pressure responsive means in each chamber, means to connect one of said pressure responsive means to the governor, means to vent the chamber containing the pressure responsive means connected to the governor, and means controlled by the pressure responsive means in the other chamber to regulate opening and closing oi the venting means.

30. In a governor speed setting regulator for a motor driven compressor comprising casings having chambers therein, pressure responsive means in each chamber, means to connect one of said pressure responsive means to the governor, means to control movement of the pressure responsive means connected to the last said means, and mea ns associated with the pressure responsive means in the other chamber to actuate the last said means.

31. In a regulator for a motor driven fluid compressor including a governor comprising a casing having chambers each subjected to a different pressure, pressure responsive means in each chamber, inter-connected movable levers to connect the governor to one of said pressure responsive means, means to vent one of said chambers to the atmosphere, and a valve to open and close the last means controlled by the pressure responsive means in the unvented chamber.

32. In a regulator for a motor driven iluid compressor including a governor comprising a casing having chambers each subjected to a diil'erent pressure, pressure responsive means in each chamber, inter-connected movable levers to connect the governor to one of said pressure responsive means, means to vent the chamber having the pressure responsive means connected to the governor, means to transmit movement of the pressure responsive means in another chamber, and a valve on the last said means to open and close the venting means.

CHARLES S. BAKER. 

